"I've sustained a vocal injury and been told I cannot sing for a week. Seriously I felt something snap, it was very frightening," she explained. "I am so, so sorry. I'm so sorry to all the fans, I was desperate to still perform, but was told without question not to, so as not to do permanent damage."

The "Shake It Out" singer also apologized via Twitter during a doctor's visit July 12. "They have to put a camera down my throat," she wrote. "What will they see down there. . .Jeepers. All my lost belongings. . .a few souls. . .a bat."

No word yet on whether the band plans to reschedule their missed concerts.